Existential theology, as the name for the various philosophical and theological conceptions that have been outlined in this essay, tends to denote a field of overlapping interests rather than any doctrinal coherence. The traditions from which the approaches stem are disparate, the outlooks on the possibility and shape of primarily Christian philosophy or theology advocated by the various thinkers are controversial, and their individual standpoints with regard to what is called 'existential philosophy' are contentious. As far as the intellectual history of the past century is concerned, the friendship between the philosopher Heidegger and the theologian Bultmann is doubtless one of the most important chapters in the dialogue between philosophy and theology. The fundamental experience of a person is, as Mounier emphasizes, the experience of being spoken to, that is, the second-person experience, or, as Mounier says with reference to Buber's philosophy of dialogue, the precedence of the You before the I, the affirmation of self-alienation.